/usr/share/z-push/lib/exceptions/ is in z-push-common 2.3.8-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/z-push/lib/exceptions/authenticationrequiredexception.php
/usr/share/z-push/lib/exceptions/fatalexception.php
/usr/share/z-push/lib/exceptions/fatalmisconfigurationexception.php
/usr/share/z-push/lib/exceptions/fatalnotimplementedexception.php
/usr/share/z-push/lib/exceptions/httpreturncodeexception.php
/usr/share/z-push/lib/exceptions/nohierarchycacheavailableexception.php
/usr/share/z-push/lib/exceptions/nopostrequestexception.php
/usr/share/z-push/lib/exceptions/notimplementedexception.php
/usr/share/z-push/lib/exceptions/provisioningrequiredexception.php
/usr/share/z-push/lib/exceptions/serviceunavailableexception.php
/usr/share/z-push/lib/exceptions/stateinvalidexception.php
/usr/share/z-push/lib/exceptions/statenotfoundexception.php
/usr/share/z-push/lib/exceptions/statenotyetavailableexception.php
/usr/share/z-push/lib/exceptions/statusexception.php
/usr/share/z-push/lib/exceptions/syncobjectbrokenexception.php
/usr/share/z-push/lib/exceptions/unavailableexception.php
/usr/share/z-push/lib/exceptions/wbxmlexception.php
/usr/share/z-push/lib/exceptions/zpushexception.php